A million-dollar bounty was offered today for the capture of former police officer Christopher Dorner who is suspected of killing three people in retaliation for being sacked.

Announcing the reward, Los Angeles mayor Antonio Villaraigosa said his “reign of terror” must end as police continued their biggest manhunt.

The search is focused in the snow-covered San Bernardino mountains since a truck belonging to Dorner was found burning near the ski resort community of Big Bear Lake on Thursday.

The ex-LAPD officer and Navy lieutenant was named as a suspect in the murder of a campus security officer and his fiancée, the daughter of a Los Angeles police captain blamed by Dorner for his dismissal.

Keith Lawrence, 27, and Monica Quan, 28, were shot dead last Sunday in their car in the city of Irvine, south of Los Angeles. Dorner, 33, is thought to have shot at two police officers, grazing one, on Thursday. A few hours later two policemen were ambushed in their patrol car in the town of Riverside. One was killed and the other wounded.

A rambling manifesto posted on Dorner’s Facebook page last week claimed he was wrongly fired from the LAPD in September 2008 and vowed to seek revenge by unleashing “unconventional and asymmetrical warfare” on police officers and their families.

The BBC says court papers show he was fired after making a complaint against his field training officer, saying she had kicked a suspect, a schizophrenic man with severe dementia, during an arrest.

LAPD chief Charlie Beck said the reward was raised from private donations, police unions, businesses and city and county governments.

Mr Beck called the spate of violence “an act of domestic terrorism”, adding: “This is a man who has targeted those who we entrust to protect the public. His actions cannot go unanswered.”

Yesterday actor Charlie Sheen made a plea for Dorner to come forward. He said: “You mention me in your manifesto so thank you for your kind words. I’m urging you to call me and let’s figure out how to end this thing.”